This proposal is a request for funds to purchase a JEOL JEM-1210 transmission electron microscope to be located in the Department of Anatomy at the University of South Dakota School of Medicine. This microscope will be accessible to Major Users and other faculty through the establishment of a new Multi-User Electron Microscope Facility. This instrumentation will replace our present instruments which consist of two 25 year-old RCA EMU electron microscopes. The JEOL JEM-1210 electron microscope provides a superior imaging system and several unique and important features needed to assist with the projects described in this proposal. Dr. Timms will investigate the ultrastructural localization of specific components of the basal lamina and stroma in rat prostate tissue using quantitative, indirect, immunogold cytochemistry in order to understand the organization of the stromal compartment in fetal and neonatal development of the gland. Dr. Washburn will study the immunocytochemical localization of adhesion molecules on the Mycoplasma arthritides cell and structural interactions between M. arthritides and host cells. Dr. Lindahl will examine the cytochemical localization of mammalian liver aldehyde dehydrogenases. Dr Goodman will characterize the ultrastructure and morphology of lung tissue in animal models of pulmonary edema, in addition to examining the intercellular junctions and integrity of monolayer cultures of pulmonary alveolar epithelium. Dr. Eyster will investigate the immunolocalization of protein kinase C in macaque corpora lutea during the luteal phase and correlate these finding with current studies of the corpus luteum. The improved optical resolution capabilities of the JEOL JEM-1210 electron microscope over the present microscopes will substantially enhance our research capabilities at the University of South Dakota School of Medicine and will certainly augment the projects described in this proposal.